The goal of this project is to understand the mechanisms that control the expression of late genes in Herpes Simplex Virus 1 (HSV-1). This will be done by defining the DNA sequences involved int he regulation of a model HSV-1 late gene, that which codes for the glycoprotein C (gC) gene. The late gene regulatory sequences will be identified initially by establishing boundaries for the sequences that are necessary for accurate regulation of expression. This will be followed by a detailed mutational analysis to determine the requirement for individual bases within this region for accurate regulation. Other HSV-1 late genes will then be examined in a similar fashion to determine whether there are consensus sequence elements necessary for the regulation of all late genes. Assuming that cis-acting elements are found, a search will be initiated to establish the identity of factors that interact either directly or indirectly with such sequence elements that are necessary for late gene regulation. This research is designed to increase our understanding of the molecular genetics of herpesviruses by studying the regulation of an important class of HSV-1 genes, and hopefully will contribute to an understanding of gene expression in virtually all biological systems.